Commonly assigned U.S. Pat. No. 7,391,315, the disclosure which is hereby incorporated by reference in its entirety, discloses a security system that uses various audio sensors as audio microphones located at one or more premises. In one non-limiting embodiment set forth in the '315 patent, the audio sensors receive audio signals and convert the audio signals to digitized audio signals. An audio sensor can receive audio signals and converts the audio signals to digitized audio signals, which can be processed at a central processor. In some aspects, the remote security or fire alarm systems can generate “reports” and transmit the reports to a central station alarm receiver.
The central station alarm receiver (hereinafter identified as an “alarm receiver”), accepts incoming calls or connections with “reports” from remote security or fire-alarm systems, through a variety of communication paths. The most common communications paths are PSTN dial-up circuits, point-to-point radio circuits and/or the internet. The “reports” generated by conventional security or fire-alarm systems include alarm messages, equipment status messages, and periodic communications-check messages.
For connections over PSTN dial-up and point-to-point radio circuits, some models of alarm receivers use plug-in circuit boards called “line cards”, or “channel-cards”, to allow flexibility in the number and/or type of communication circuits supported by the alarm receiver. In general, line cards have an interface to the alarm receiver main processor system, and implement one or more modem circuits than can communicate with the remote security or fire-alarm systems. For each modem, the line card typically also has a physical interface connector for the corresponding communications circuit.
In the United States, central station facilities generally only use alarm receiver systems that are listed under UL (Underwriters Laboratories) standard 1610: “Central Station Burglar-Alarm Units,” the disclosure which is hereby incorporated by reference in its entirety. If the central station operates as a UL-listed facility, it is mandatory to use alarm receivers listed under this UL standard.
The UL-1610 standard requires that an alarm receiver be able to operate independently of any central station “automation software.” The most practical way to meet this requirement is for the alarm receiver to process internally any and all reports it receives from remote security or fire alarm systems, regardless of the communications path (PSTN dial-up, point-to-point radio, internet) through which the report was received.
In addition to validating the received report, and generating any automatic message-receipt acknowledgement required by the remote system, the alarm receiver must be capable of independently performing these actions:
a) presenting the report information (including the unique account-number information identifying the reporting system) on a display device built into the alarm receiver;
b) generating an audible and/or visible annunciation of new reports;
c) logging the report information in a non-volatile memory system, for later review or further processing;
d) providing some mechanism for a human operator to acknowledge physically receipt of the report; and
e) directing a copy of each report to a printing device, which may be a part of the alarm receiver or electronically connected to the alarm receiver.
It should be understood that the UL standard allows operator-managed acknowledgement to be performed at an operator console that is part of the central station automation system, which is a software-based system. However, the alarm receiver must be capable of reverting to local (front-panel) operator-managed acknowledgement if the automation system becomes unavailable.
After the alarm receiver has accomplished these processing functions, it can optionally forward the alarm report data to any “automation software” that is in use at the central station.
In practice (particularly where several alarm receivers are installed in a central station facility), operators don't normally interface directly with alarm receivers. Instead, they handle received alarm reports on computer workstations that are part of the automation system. However, alarm receiver conformance to the UL 1610 standard ensures that the central station can respond to alarms if the automation system becomes unavailable.
In this UL-specified framework for communications between alarm receivers and conventional remote security or fire alarm systems, there are some important common characteristics of PSTN dial-up and/or point-to-point radio connections between the remote system and the central station:
a) except for a few special cases, the data-flow is unidirectional . . . from the remote system at the premises to the alarm receiver in the central station;
b) each connection is maintained only long enough for the remote system to transmit the report and receive any automatic message-acknowledgement from the alarm receiver; and
c) report data (alarm messages, remote system status messages, periodic communication-check messages) are always processed internally by the alarm receiver, before the report information is forwarded to any central station “automation software.”
These special cases are unique features in the remote system that can be controlled from the central station. To allow the bi-directional communications necessary for these remote system features, matching non-standard communications protocols and processes should be implemented on both the remote (premises) system and the alarm receiver. For the alarm receiver to retain its necessary UL listing, these non-standard protocols and processes must be compliant with the UL 1610 standard.